University affiliated investigators, collectively known as the Brain Tumor Study Group, are cooperating in a continuous effort, conducting Phase III clinical trials to evaluate chemotherapy, radiation therapy and combinations thereof (multi-modality therapy) following definitive surgery in the treatment of brain tumors (malignant gliomas). New chemotherapeutic agents are also being tested in Phase II clinical trials in order to make the selection of chemotherapeutic agents for future Phase III trials more meaningful. In addition to testing the efficacy of various treatments in malignant brain tumor, radiation effects and drug toxicity are being assessed. Data is also being accumulated that will provide a basic understanding of the biology, natural course and peculiarities of the disease entity under investigation. Work completed has shown that radiation therapy alone and in combination with the nitrosoureas significantly extends the median survival of brain tumor patients.